The present invention relates to a mobile phone charger, and more particularly to a mobile phone charger that includes internal in-car hand-free enabling circuit and high-sensitive microphone and therefore permits a mobile phone disposed in the charging socket to enter into a hand-free mode while the microphone picks up a sound source at the site of charging. The picked sound source may be transmitted via a communication network to which the mobile phone is connected. A caller of an in-coming call over the mobile phone under charging may enter a preset code to perform a sound monitoring from a remote position.
A conventional remote sound monitoring device designed for securing purpose usually has a limited data transmission distance within the range from 50M to 500M, depending on the radio frequency designed for the device. And, such remote sound monitoring device transmits data in the manner of analog transmission and is therefore subject to bugged by other detecting devices. Moreover, such remote sound monitoring device is powered by batteries and not adapted to monitor for a prolonged time period. These problems prevent the conventional remote sound monitoring device from working ideally.
A primary object of the present invention is to provide a mobile phone charger that may also function as a remote sound monitoring device to transmit picked sound via a communication network to which a mobile phone disposed in the charger is connected.
In an aspect of the present invention, the charger includes a handset w/battery charging socket that is electrically connected to an in-car hand-free enabling circuit internally provided in the charger. When a mobile phone is disposed in the handset w/battery charging socket, it is automatically switched into the hand-free mode, and the ringing, receiving, and calling functions of the mobile phone are replaced by a high-sensitive microphone internally provided in the charger.
In another aspect of the present invention, the charger internally includes a high-sensitive microphone and related amplifying circuit and a central processing unit (CPU). When a handset of a mobile phone is disposed in a handset w/battery charging socket on the charger, an in-car hand-free enabling circuit in the charger is enabled for the handset in the charger to charge while entering into a hand-free mode and in a standby state. At this point, the charger substitutes for the handset and the CPU in the charger automatically receives signals of in-coming call over the mobile phone and the mobile phone does not ring. On receipt of a signal of an in-coming call, the CPU conditionally turns on the high-sensitive microphone for the latter to pick up sound at the site of charging and transmit the picked sound via a cellular communication network to which the charging handset is connected, so that a caller may perform a sound monitoring from a remote position.
In a further aspect of the present invention, the charger includes a CPU, a high-sensitive microphone and related amplifying circuit, and a DTMF decoder. When a mobile phone is disposed in the charge and the CPU receives a signal of an in-coming call, the CPU beeps to prompt the caller to enter a security code within a preset time period. The entered code is decoded and compared by the DTMF decoder with a code preset in the CPU. Only when the entered code is determined as correct will the high-sensitive microphone be turned on to pick up sound at the site of charging and transmit the picked sound via a cellular communication network to which the charging handset is connected. Therefore, the sound monitoring from a remote position is performed in a strictly confidential manner.